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Zuzana Vasková Jan Moncol Maria Korabik Dušan Valigura Jozef Švorec Tadeusz Lis Marian Valko Milan Melník 《Polyhedron》2010
A new complex of unusual composition [Cu(3-O2Nbz)2(nia)(H2O)2] (1) (nia = nicotinamide, 3-O2Nbz = 3-nitrobenzoate) has been prepared and studied together with two other complexes of composition [Cu(4-O2Nbz)2(nia)2(H2O)2] (2) and [Cu(4-O2Nbz)2(nia)2]?(4-O2NbzH)2 (3) (4-O2Nbz = 4-nitrobenzoate). The composition of all complexes has been determined by elemental analysis, the complexes have been studied by electronic, infrared and EPR spectroscopy, as well as by magnetization measurements over the temperature range 1.8–300 K, and their structures have been solved. The structure of complex (1) consists of molecules, where Cu(II) atom is monodentately coordinated by the pair of 3-nitrobenzoato anions in trans -positions together with water and nicotinamide molecules, forming nearly tetragonal basal plane, and by another water molecule in axial position of tetragonal-pyramidal coordination polyhedron. The neighboring molecule coordination polyhedron basal planes are coplanar and allow formation of supramolecular dimers with strong H-bonds between hydrogen atoms from equatorially coordinated water molecules and uncoordinated carboxylate oxygen atoms thus giving the nearest Cu?Cu distance of 4.886(2) Å. Magnetization measurements showed that complex (1) exhibits maximum of magnetic susceptibility at 6.5 K and a fit to Bleaney-Bowers equation gave singlet–triplet energy gap 2J = −6.25 cm−1, and zJ′ = −0.03 cm−1. This might be an experimental proof that the carboxylate bridges extended with hydrogen bonds are the pathway of the spin–spin interactions. The temperature dependence of changes in EPR spectra of (1) and the spectrum at 4.2 K have confirmed its hydrogen bonded dimeric structure. The calculated Cu?Cu distance 4.8 Å is in very good agreement with the value obtained from crystal structure. The complexes (2) and (3) at 300 K exhibit magnetic moment μeff = 1.98 B.M. and μeff = 1.84 B.M., respectively. These values practically do not change with lowering the temperature up to 5 K and only small drops to μeff = 1.87 B.M. (for (2)) and μeff = 1.79 B.M. (for (3)) at 1.8 K have been observed. The EPR spectra of complex (2) at room temperature as well as at 77 K are of axial type with g⊥ = 2.062 and g|| = 2.285 and exhibit resolved parallel hyperfine splitting with A|| = 160 Gauss. The EPR spectra of complex (3) at room temperature as well as at 77 K are of axial type with g⊥ = 2.065 and g|| = 2.235 and exhibit unresolved parallel hyperfine splitting. EPR spectra of (2) and (3) are consistent with the X-ray structure. 相似文献
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Repická Zuzana Moncol Jan Puchoňová Miroslava Jorík Vladimír Mikloš Dušan Lis Tadeusz Padělková Zdenka Mazúr Milan Valigura Dušan 《Structural chemistry》2010,21(5):1093-1102
Novel copper(II) X-salicylate complexes with N,N-diethylnicotinamide (dena) of the formula [Cu(RCOO)2(dena)2(H2O)2] (RCOO = 3-methylsalicylate anion (3-Mesal, 1), 4-methylsalicylate anion (4-Mesal, 2), 5-methylsalicylate anion (5-Mesal, 3), 5-methoxysalicylate anion (5-MeOsal, 4) or 4-methoxysalicylate anion (4-MeOsal, 5)), and complex [Cu(3-MeOsal)2(dena)2(H2O)2]∙2H2O (3-MeOsal = 3-methoxysalicylate anion (6)) have been prepared in the crystalline forms and characterized by spectroscopic methods (IR, Vis–UV, EPR). All the compounds
according to their composition (1–5) seem to possess octahedral copper(II) stereochemistry. The complex 1 has been prepared in two different forms. X-ray analyses of the complexes 1, 4, and 5 were carried out and they featured a tetragonal-bipyramidal geometry around the copper atoms. The tetragonal planes are created
by X-salicylate anions bonded to the copper(II) atoms via unidentate carboxylate oxygen atoms and the pyridine ring nitrogen
atoms of the neutral ligand N,N-diethylnicotinamide, while in axial positions are water molecules. The two forms of complex 1 present conformation polymorphs and supramolecular isomers. 相似文献
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Dr. Maria Korabik Zuzana Repická Ladislav Martiška Jan Moncol Jozef Švorec Zdeňka Padělková Tadeusz Lis Milan Mazúr Prof. Dr. Dušan Valigura 《无机化学与普通化学杂志》2011,637(2):224-231
Polymeric salicylatocopper(II) complexes of unusual composition [C u(X‐ sal)2( μ‐denia)(H2O)]n [denia = diethylnicotinamide, and X‐sal = 5‐methylsalicylate ( 1 ), 3‐methylsalicylate ( 2 ), 4‐methoxysalicylate ( 3 ), 3,5‐dichlorosalicylate ( 4 ) and 3,5‐dibromosalicylate ( 5 )] were synthesized and characterized. Magnetic measurements were performed in the temperature range 1.8–300 K. The structural unit of all complexes consists of a CuII atom, which is monodentately coordinated by the pair of X‐salicylate anions in trans positions. Water and the diethylnicotinamide ligand occupy the other two basal plane positions of the tetragonal pyramid. The axial positions are occupied by a diethylnicotinamide oxygen atom of neighboring structural units, thus forming a spiral polymeric structure parallel to b axis. Magnetic measurements showed that all complexes 1 – 5 exhibit a susceptibility maximum at about 6–8 K. The obtained data fit to Bleaney–Bowers equation gave singlet‐triplet energy gaps 2J = –8.60 cm–1 for 1 , 2J = –6.57 cm–1 for 2 , 2J = –8.57 cm–1 for 3 , 2J = –6.82 cm–1 for 4 , and 2J = –6.45 cm–1 for 5 . The supramolecular structure based on hydrogen bonds [described by supramolecular synthons R22(10) and R22(12)] is the pathway for antiferromagnetic interactions of the magnetically coupled pairs of copper atoms of neighboring chains within the 2D supramolecular layers. The results of the magnetic measurements suggest involvement of the COO groups in the magnetic interaction pathway for all five complexes. 相似文献
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Investigation of salicylatocopper complexes in the presence of a nitrogen donor ligand is a growing research area due to the interesting mimetic activities of such complexes. Here, three X-salicylatocopper (where X = 3-methyl, or 4-methoxy) complexes with three different N-donor ligands, [Cu(μ-menia)(3-Mesal)2(menia)(H2O)]2 (I), Cu(3-Mesal)2(denia)2(H2O)2 (II), Cu(4-MeOsal)2(2-pyme)2 (III), are presented (where 3-Mesal = 3-methysalicylate, 4-MeOsal = 4-methoxysalicylate, menia = N-methylnicotinamide, 2-pyme = 2-pyridylmethanol). The complexes were characterized by elemental analysis, IR and UV-VIS spectrophotometry. Cyclic voltammetry and the superoxide dismutase activity of the prepared complexes in solution were measured and the complexes were characterized by means of the inhibition concentration IC50. In addition, the superoxide dismutase (SOD) activity of these complexes was compared with those of the parent ligand copper acetate, native SOD enzyme, and the related copper complexes containing non-steroidal anti-inflammatory drugs. The resulting SOD activity was correlated to the composition, structure and redox stability of the prepared complexes. The best value of the inhibition concentration was found for complex I (IC50 = 2.24 µM), which classifies this complex into a group of good superoxide scavengers. 相似文献
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Jan Moncol Zuzana Vasková Petra Stachová Jozef Svorec Reijo Sillanpää Milan Mazúr Dušan Valigura 《Journal of chemical crystallography》2010,40(2):179-184